It is beneficial to be able to regulate a rate of fluid flow out of, or into, a formation or zone intersected by a wellbore. Downhole chokes have been developed in the past to enable regulation of production and/or injection flow rates. However, improvements are needed to address certain situations encountered in the downhole environment.
For example, a typical downhole choke is configured at the surface to permit a certain flow rate when a certain pressure differential of a certain density fluid is applied across the choke. Then, the choke is installed in the wellbore. If conditions change (such as increased water production, decreased reservoir pressure, etc.) and it is desired to change the choke settings, the choke must be retrieved from the wellbore, reconfigured and then installed in the wellbore in an expensive and time-consuming process.
If conditions change again, the process must be repeated again. In particular, if the pressure differential across the choke changes, the flow rate through the choke also changes.
Another type of downhole choke can be adjusted from the surface using hydraulic control lines. Unfortunately, the choke still cannot respond to varying downhole conditions (such as changing pressure differentials) to maintain a substantially constant flow rate.
Therefore, it may be seen that improvements are needed in downhole flow regulating systems. It is an object of the present invention to provide such improvements.